Flawless Cutting of Tubing and Control Lines by Mechanical Pipe Cutter in Challenging Well Condition Provides an Environmental Friendly Alternative: A Case Study from Brunei

Abstract

The Electro-Mechanical Pipe Cutter (MPC) is a non-ballistic & non-chemical wireline deployed alternative cutter tool for parting downhole tubular in the process of well abandonment, pipe recovery and retrieving of packer elements. This case study showcases its application in two wells with different challenges in cutting 4.5" tubing viz., (i) with multiple control lines to facilitate fishing operations and (ii) under compression in a highly deviated trajectory. In Well A, Brunei offshore, the position of the tubing and orientation of the control lines were challenging for ballistic option, along with the possibility of scarring the 9-7/8" casing during the cutting operation. Thus, 3-1/8" OD MPC was used for this job to cut near the coupling, ensuring optimum stand off from casing wall aiming to achieve cutting the control lines in tension. Dual cut were designed to allow the room for a safe cut zone. The primary cut was performed near middle of the joint at ∼1985m, with the tubing in tension. The cut was initiated at a very slow feed (0.2 mm/min) and motor rates (4000rpm), which was gradually increased once the cutting was stable. After the accomplishment of the tubing cut, the parameters were again reduced to carefully cutting through control line. The tubing was successfully retrieved with smooth cut without any over pull indicating it to be completely free. The flawless cutting operation was performed in less than one hour with outmost efficiency. In another highly inclined Well B, Brunei offshore, MPC was chosen over ballistic because it was needed to be conveyed by tractor and ballistic shock has potential to damage it during the operation. Also the advantage of MPC to perform multiple cuts in one run, made it a preferred choice. In this well, multiple cuts were performed to weaken the joint connection of the tubing to allow the rig to pull it free. It was to overcome the adversity posed by high inclination and the pipe under compression. Three cuts were performed at ∼2996 m, each 20 cm apart with an OD of nearly 4.609". After completion of the job, the circulation was performed with surface return, indicating successful execution and the tubing was retrieved on surface showing a clean cut. This case study shows the appropriate planning and execution of the mechanical pipe cutter can provide an efficient, environment friendly and safe alternative to cut tubing and control line in the challenging condition especially when an explosive and chemical cutter options are not considered suitable.